18 
THE NAUTILUS. 
before me fully support this opinion. Unfortunately none of them 
are young enough to show the apex. The youngest of them, 
although not half the diameter of the adult, show the same almost 
imperceptible degree of tapering. 
P. Fordianus Pilsbry. 
Shell cylindrical, white, thin ; spire hardly tapering, but last 
whorl notably wider. Remaining whorls 4J, sculptured as 
in the last species, but the next-to-the-last whorl is distinctly 
narrower than the preceding whorl. Aperture nearly one- 
half the length of the shell; outer lip thin, simple ; colu¬ 
mella straight, a trifle deflected toward the left below. Alt. 
19, diam. 7? mm. 
Habitat unknown. The specimens were presented to the Acad¬ 
emy by Mr. John Ford. 
This species is distinguished from the preceding by its straight, 
not sigmoid columella, and by the fewer remaining whorls. As the 
last character might possibly be the result of greater age, I do not 
now attach much importance to it, although it will probably prove 
to be a constant specific feature. 
SOUTHERN SHELLS IN MISSOURI. 
BY F. A. SAMPSON, SEDALIA, MO. 
In the March Nautilus there is a reference to Helicina orbiculata 
having been collected in Stone county, Missouri, “ probably near its 
northern limits.” I have it in my collection from three other 
counties in Missouri: Jasper, Barry, and Macdonald, all of them 
being near the southern line of the state. 
Of some other southern species I have specimens from places fur¬ 
ther north, a list of which is here given : 
Bulimulus dealbatus Say, from the counties of Macdonald, Barry, 
Douglas, Camden and Cooper, the two latter being in the central 
part of the state. 
Polygyra triodontoides Bland, from Barry. 
P. jaclcsoni Bland, from Jasper, Barry, Macdonald, Dade and 
Camden. 
P. dorfeuilliana Lea, from Howell and Douglas. 
